• Journal of the Korean Institute of Gas
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• v.16 no.1
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• pp.1-7
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• 2012

The present study has been carried out to analyze the flow characteristics in the inlet expasion duct of a heat recovery steam generator by using numerical flow analysis. The inlet of HRSG corresponds the outlet of gas turbine exit and the flow after gas turbine has strong swirl flow and turbulence. The inlet flow condition of HRSG should be included the exit flow characteristics of gas turbine. The present numerical analysis adopted the flow analysis result of gas turbine exit flow as a inlet flow condition of HRSG analysis. Because the flow characteristics in the inlet duct of the tube bank is strongly related to the performance of a HRSG, it is most important for the optimal design of HGSG to understanding the flow phenomena in the inlet duct of HRSG. From the present study, the position of breakpoint in the inlet expansion duct should be lower than the reference breakpoint position for the optimal flow uniformity before the tube bank.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.2
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• pp.120-130
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• 2000

A flow uniformity in a duct cooler of duct system of FGD(Flue Gas Desulfurization) linking a reheater and a absorber has been investigated in the present study. For this purpose, the flow characteristics according to the geometry of a vertical and horizontal vane in a curved duct of the duct system has been examined with the aid of a numerical simulation. The results indicate that the vertical vane with a little deflection toward a recirculation region makes the flow distribution in the duct cooler more uniform than that without deflection, and horizontal vane does not effect the change of the flow distribution for an angle of inclination. The mean flow uniform factor shows its maximum for duct system without the vane(case NP) and its minimum for the vertical vane with a little deflection(case P-0.8-0) .

• Proceedings of the Korean Fiber Society Conference
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• 2007.11a
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• pp.65-68
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• 2007

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.6
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• pp.878-883
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• 2011

Effect of flow uniformity on the reaction characteristics of a catalytic combustor for high temperature fuel cell system has been experimentally investigated in the present study. One of the most important factor in designing catalytic combustion is to avoid hot spot in catalysts. In this regard, it is very important to secure flow uniformity of combustor inlet. A couple of perforated plates were applied at the front of catalyst region as flow uniformity device with minimal pressure drop. Results show that the velocity and temperature profile became more uniform when applying the flow uniformity device. CO and $CH_4$ emissions at the combustor exit were decreased and the average exit temperature was slightly increased with the flow uniformity device.

• Journal of the Korean Society of Visualization
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• v.20 no.3
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• pp.86-93
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• 2022

An electrostatic precipitator (ESP) is an industrial post processing facility for high efficiency dust mitigation. Uniformity of the flow passing through the inlet duct leading into the main chamber is important for efficient reduction of dust. To examine flow uniformity, this study conducted a numerical analysis of the flow within a scale-down ESP inlet duct. Magnetic resonance velocimetry (MRV) results from a prior study were utilized to validate the Reynolds-averaged Navier-Stokes (RANS) numerical simulations. Both the experimental and computational results displayed a similar recirculation zone shape and normalized velocity profile near the duct outlet for the baseline geometry. To optimize the uniformity of the flow, the number of guide vanes was modified, and the guide vanes were partially extended straight upward. Design evaluation is done based on the outlet velocity distribution and mass flowrate balance between the two outlets. Simulation results indicate that the vane extension is critical for flow optimization in curved ESP ducts.

• Plant Journal
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• v.9 no.3
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• pp.48-52
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• 2013

In this study, the internal flow field of SCR Denitrification Plant was simulated by using Computational Fluid Dynamics(CFD). In order to analyze the uniformity of flow field, an interpretation on the pre-existing facilities was performed, and some moot points were identified and compensated through this analysis. The compensatory methods include the installation of the Porous Plate below the bottom of the Baffle to create uniform flow and also, and the Guide Vane was also placed in the bend of pipe to guide the flow uniformly. Lastly, the Baffle was installed to deduct equalized space distribution of the air flow, initially flowed into the SCR Plant.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.151-154
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• 2011

$NO_x$ 제어 기술로는 크게 연소 전 탈질, 연소 개선 및 연소 후 탈질 기술로 구분할 수 있으며, 연소 후 탈질 기술에 속하는 SCR은 촉매를 사용하여 $NO_x$를 환원하는 대표적인 배연탈질기술이다. SCR의 $NO_x$ 저감 성능은 촉매 요인(촉매 구성물질, 형태, 공간속도 등)과 배가스의 온도, 유속 분포, 공정 운전 조건 등의 다양한 인자에 의해 좌우되는데 특히, 촉매층으로 유입되는 유동의 균일도는 가장 중요한 요소가 된다. 유동이 균일하지 않을 경우 촉매 전단에 편류가 발생하게 될 것이며 일정 촉매만 사용하게 되어 촉매 사용주기 감소 및 SCR 성능 저하를 초래할 수 있기 때문이다. 본 연구에서는 3차원 수치 해석 기법을 이용하여 설계 초기의 SCR 반응기 내 유동 특성을 모사하여 기류 균일도 여부를 확인하고, SCR 내 유동 균일도를 최적화시키기 위한 설계를 목적으로 설치하는 가이드 베인과 배플, 다공판이 반응기 내부 유동 및 촉매층의 기류 균일도에 미치는 영향에 대하여 연구를 수행하였다. 그 결과, 유동 개선을 위해 인입 덕트 곡관부에 가이드 베인을 설치하여 처리가스를 적절하게 배분시키고, 반응기 상단에 3단 배플을 설치한 결과 반응기 내부 유동의 편류 개선에 매우 효과적임을 알 수 있었다. 또한 다공판을 예비 촉매층 하단부 위치에 추가로 설치함에 따라 유동을 한번 더 완충시킬 수 있어 기류 균일도가 매우 양호해짐을 알 수 있었다.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.4
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• pp.406-412
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• 2007

An experimental study on the design of a catalytic combustor for 1.6 kW MCFC system has been performed. The roles of the catalytic combustor are to completely burn anode off-gas and to supply sufficient $CO_2$ to cathode channels. In order to avoid hot spot or fuel slippage, flow uniformity at the catalyst inlet was achieved by installing two crossing perforated plates between the catalyst and the mixing chamber with minimal pressure drop. A Pd/Ce/Ni-$Al_2O_3$ catalyst was used for complete combustion of the off-gas at GHSV=36,000.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.12
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• pp.1065-1072
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• 2014

The shape of an impeller splitter for a dual-inlet centrifugal blower was optimized to enhance the blower performance. Two design variable, the normalized chord and pitch of a splitter, were used to evaluate the blower performance and internal flow fields based on the three-dimensional flow analysis. The blower performance obtained using this numerical simulation had a maximum error of 4 percent compared to that in an experiment at the design flow condition. The shape optimization of the splitter successfully increased the blower efficiency and pressure by 3.65 and 1.14 percent compared to the reference values. The blower performance was increased by reducing the flow separation near the blade suction surface by optimizing the shape of the splitter, which produced a pressure increase at the outlet of the volute casing.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.415-420
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• 2009

Selective Catalytic Reduction(SCR) has been used for the reduction of $NO_x$ in a steam supply boiler. Recently, the reduction of $NO_x$ becomes an important research field because of its negative effect on an environment. Shape optimization of circular poles installed in the chamber, which is located in upstream of a SCR, has been performed using response surface method and three-dimensional Navier-Stokes analysis to enhance gas flow uniformity. Three design parameters, diameter, arranging angle and stretching ratio of circular poles, are considered in the present study. Throughout the shape optimization of a circular pole, gas flow uniformity is successfully increased by decreasing local recirculation flow in a square duct chamber. Recirculation flow observed in the corner of the square duct can be reduced by proper installation of a guide vane or a blunt body. Detailed flow characteristics are also analyzed and discussed.